Xephyr - X server outputting to a window on a pre-existing X display


   Xephyr [:display] [option ...]


   Xephyr  is  a  kdrive server that outputs to a window on a pre-existing
   "host" X display.  Think Xnest but with support for  modern  extensions
   like composite, damage and randr.

   Unlike  Xnest which is an X proxy, i.e.  limited to the capabilities of
   the host X server, Xephyr is a real X server  which  uses  the  host  X
   server window as "framebuffer" via fast SHM XImages.

   It  also  has  support  for  "visually"  debugging  what  the server is


   The server accepts all the  standard  options  of  Xserver(1)  and  the
   following additional options:

   -screen widthxheight
           sets the screen size.

   -parent id
           uses  existing  window  id  .   If a -screen argument follows a
           -parent argument,  this  screen  is  embedded  into  the  given

           set 'cursor acceleration': The host's cursor is reused. This is
           only really there to aid debugging by  avoiding  server  paints
           for the cursor. Performance improvement is negligible.

           Allow  the  Xephyr  window  to be resized, even if not embedded
           into a parent window. By default, the Xephyr window has a fixed

           Disable grabbing the keyboard and mouse.


   Send  a  SIGUSR1  to the server (e.g. pkill -USR1 Xephyr) to toggle the
   debugging mode.  In this mode red  rectangles  are  painted  to  screen
   areas  getting  painted  before painting the actual content.  The delay
   between this can be altered by setting a  XEPHYR_PAUSE  env  var  to  a
   value in micro seconds.


   * Rotated displays are currently updated via full blits. This is slower
     than a normal orientated display. Debug mode will therefore not be of
     much use rotated.

   * The '-host-cursor' cursor is static in its appearance.

   * The  build gets a warning about 'nanosleep'. I think the various '-D'
     build flags are causing this. I haven't figured as yet  how  to  work
     round it. It doesn't appear to break anything however.

   * Keyboard handling is basic but works.

   * Mouse button 5 probably won't work.


   X(7), Xserver(1)


   Matthew Allum <mallum@o-hand.com> 2004


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